The media icon, 71, did not hold her tongue when it came to dishing out her thoughts on the Gavin & Stacey star.
She was speaking to her fellow The X Factor pal Louis Walsh as they discussed how the star had played the “LA life” to his advantage.
James moved to Hollywood to further his career and landed his very own late-night talk show, The Late Late Show.
Sharon took aim at the star for constantly “throwing out names” as she insisted that that he liked to brag about his A-list connections at any possible opportunity.
Recalling a time she complimented the star on his footwear, Sharon said: “I’d say ‘I love your shoes’ and he’d say ‘ yeah Stella McCartney’.
“I would think, I didn’t ask where you got them? I don’t care!”
She went on to add: “He constantly, constantly throws out names.
“When he got to America, he played the LA game really well!”
Louis then interjected: “Kissing all the right people.”
“Oh God,” Sharon said back before Louis name dropped Vogue editor Anna Wintour as one of those people as he made a slew of kissing noises.
Sharon then said: “Oh she [Anna] loves him!
“But, who loves Anna Wintour?
“I think she’s the C-word.”
Louis concurred as he said: “Yeah she is and Ellen DeGeneres, she’s the same.”
Sharon then pretended to vomit at the mention of the former talk show host’s name as she indicated a strong dislike towards her.
Fans were left on the edge of their seats at Sharon spilling all of the A-list drama on the show.
One fan penned of the scenes: “The TEA this series is SCORCHING.”
Another insisted: “Oh she’s earning that fee.”
Before a third wrote: “Oh this is the Sharon I love.”
Celebrity Big Brother line-up
So who are the 13 stars expected to appear in the Celebrity Big Brother house? The Sun’s Jamie Downham takes a look…
Sharon Osbourne – TV legend – who is thought to be on a megabucks deal – said she was doing the show for “a good time not a long time”
Louis Walsh – Irish boyband manager who has never knowingly backed down from a fight. Sure to be a huge presence in the house.
Ekin-Su Cülcüloğlu – We know from Love Island, the Ek-ster is not above throwing about some dramatics to claw her way to the final.
Levi Roots – Reggae Reggae Sauce sauce packs a bit of a kick, but its inventor seems quite mild-mannered. Will that change under pressure?
Fern Britton – The former This Morning star called out Phillip Schofield – don’t think she won’t do the same to anyone who tangles with her.
Colson Smith – You’ll probably know him best as Corrie’s Craig Tinker – but prepare to find out he’s not much like his character.
David Potts – Ibiza Weekender’s breakout star is sure to bring a bit of the party isle to the house… but will people appreciate it?
Gary Goldsmith – Kate Middleton’s uncle is a big signing for ITV, but very much an unknown quantity among viewers.
Marisha Wallace – Top Broadway star may fill the brief of ‘American who doesn’t know what they’ve let themselves in for’.
Nikita Kuzmin – The Strictly pro is coming onto the show fresh off the show’s tour. Poor lad probably just wants a rest.
Zeze Mills – the social media star has a “no holds barred interview style” – which is just what we need in there.
Bradley Riches – The actor played sweet James McEwan in Netflix hit Heartstopper. We’ll soon find out what he’s really like.
Lauren Simon – She’s a Real Housewives of Cheshire star and you don’t get on that show by being shy and retiring.